Biological assays for analyte detection

Abstract

Fluorescence-based assay methods for detecting biological analytes in a sample. The fluorescence background in these methods is significantly lower than in conventional assay methods. Also provided are methods of attaching nucleic acids to a metallic or metalloid surface.

What is claimed is:  
     
       1. A method of detecting an analyte in a sample, the method comprising: 
       providing an opaque glass support with a surface that is in contact with the sample, wherein the analyte, if present in the sample, is labeled with a fluorochrome and is bound to the surface;  
       illuminating the surface with light at a wavelength that excites the fluorochrome; and  
       detecting fluorescent emission from the surface as an indication of the presence of the analyte in the sample.  
     
     
       2. The method of  claim 1 , wherein the analyte is bound to the surface via a capture probe that (i) binds specifically to the analyte and (ii) is immobilized on the surface. 
     
     
       3. The method of  claim 1 , wherein the analyte is a nucleic acid. 
     
     
       4. A method of detecting an analyte in a sample, the method comprising: 
       providing a reflective surface that is in contact with the sample, wherein the analyte, if present in the sample, is labeled with a fluorochrome and is bound to the surface;  
       illuminating the surface with light at a wave length that excites the fluorochrome; and  
       detecting fluorescent emission from the surface as an indicating of the presence of the analyte in the sample.  
     
     
       5. The method of  claim 4 , wherein the analyte is bound to the reflective surface via a capture probe that binds specifically to the analyte and is immobilized on the surface. 
     
     
       6. The method of  claim 4 , wherein the analyte is a nucleic acid. 
     
     
       7. The method of  claim 4 , wherein the reflective surface is a metallic or metalloid surface. 
     
     
       8. The method of  claim 7 , wherein the metallic surface is a chromium surface. 
     
     
       9. The method of  claim 7 , wherein the metallic surface is an aluminum surface. 
     
     
       10. The method of  claim 7 , wherein the metalloid surface is a silicon surface. 
     
     
       11. A method of attaching a nucleic acid to a metallic or metalloid surface, the method comprising: 
       providing a solution that contains the nucleic acid;  
       denaturing the nucleic acid in the solution;  
       applying the solution to the metallic or metalloid surface; and  
       allowing the solution to dry on the surface, thereby attaching the nucleic acid to the surface.  
     
     
       12. The method of  claim 11 , wherein the solution has a pH of at least about 11. 
     
     
       13. The method of  claim 12 , wherein the solution comprises sodium hydroxide. 
     
     
       14. The method of  claim 11 , wherein the nucleic acid is denatured by heating the solution to a temperature and for a time sufficient to denature the nucleic acid. 
     
     
       15. The method of  claim 11 , wherein the metallic surface is a chromium surface. 
     
     
       16. The method of  claim 11 , wherein the metallic surface is an aluminum surface. 
     
     
       17. The method of  claim 11 , wherein the metalloid surface is a silicon surface. 
     
     
       18. The method of  claim 4 , wherein the excitation light is directed to the surface at an angle.